Fixes 5 bugs in escalation chains, alert rules, and EDA schema:

- Fix get_escalation_chain to handle nested stage arrays [[{...}]] from LM API
- Add destinations and cc_destinations params to create/update escalation chain
- Add missing throttling_period/throttling_alerts to update_escalation_chain schema
- Add missing datapoint, instance, suppress_alert_ack_sdt to create_alert_rule schema
- Add missing suppress_alert_ack_sdt to update_alert_rule schema
- Add awx_token_id test coverage for create_eda_activation

1295 tests passing (+14 new).